Hidden Dangers of Nighttime Lights

New studies shed light on why breast cancer rates are so high in industrialized nations. Read on to find out what you can do to minimize your risk.

Night falls, so you flick on your lights. But a shocking theory has been gaining support in the past few years: that artificial light at night may contribute to breast and prostate cancers, perhaps because it turns down production of the hormone melatonin. Now two studies add weight to that idea.

It’s known that light suppresses the brain’s production of melatonin. The hormone may play a role in immunity or help slow the growth of cancer, according to Richard G. Stevens, PhD, a coauthor of the Israeli study. So how can you minimize the possible risk posed by modern lighting — without going preindustrial?

Sleep in as dark a room as possible. Use room-darkening blinds or shades if you live on a bright, urban street or have a streetlamp outside your window.

Keep a night-light in the bathroom for midnight visits instead of turning on the overhead. Even brief exposure to light can suppress melatonin. A red bulb is best: Red wavelengths cause a less precipitous drop in levels of the hormone than blue wavelengths, such as those in halogen and fluorescent lighting.

Eat breakfast by the window. A 20-minute dose of sunlight will reset your natural circadian rhythms and help ensure a healthy night time melatonin peak.